Hi,
I'm new to this forum, so this might have been up before, but I haven't been able to find anything about it so far.

Right, short version:
Just got my 32Gb J3 yesterday, topped off with a 32Gb Sandisk SDHC, have spent last evening and night filling it up with music, mostly FLAC ripped in Winamp, and a few MP3's.

Whenever I play FLAC, I quite often get this high volume short screech (white noise really) at various points during playback. Very annoying to say the least, and I'm at a loss as to what causes it. I'm using the same files that I've used on my old, but still working iRiver H140 with Rockbox, as well as Winamp, and I've got no such issues there. I don't get it with MP3's, as far as I can tell so far anyways.

Settings on my J3, I'm using Jet Effect BBE Headphones, but I get the noise no matter what setting I use.

I use a Koss Portapro headset, also used with iRiver H140 without any issues.

Apart from that noise kicking in form time to time, sound quality is good, although I'm still figuring things out here....not sure I've found my sweetspot yet

Hmmm, I think I MIGHT have found out why, after searching high and low on the net. Some guy had the same issue on a Cowon S9, or it sounded like he had the same issues anyway.
Turns out all his FLAC-files were encoded using the Flake-encoder, and not Winamp's standard 1.2.1 FLAC encoder.
I checked my own files, and it turns out that those files that I ripped yesterday using the default Winamp encoder do not have this static noise, while all the files that had noise has been ripped at some earlier time using the Flake encoder.

If that's the problem why not just re-enocde using a the standard FLAC encoder? Lossless is lossless after all. When I played about a bit with CueTools and the Flake encoder I tested/transcoded several files between the two encoders and then transcoded them back to .wav. When I calculated the CRC values of the resulting .wavs after several FLAKE to FLAC transcodes the resulting .wav values always matched. That means the encoded audio material was the same.

I'd try that before I put the additional wear and tear my optical drive. Another big plus with that will be time saved. The average transcode FLAKE to FLAC for me was just under a minute per album. I don't know how long it takes you to rip an album but I'll bet it's a lot longer than that.